CVE-2026-43886Public exploitNetwork attack vector

Unrestricted API access via partial scope validation

Published May 11, 2026 · Updated May 11, 2026

Improper privilege management in Outline 0.84.0 through 1.6.1 allows remote attackers to gain unrestricted API access through OAuth. OAuthInterface.validateScope() uses Array.some() and returns the complete requested scope array when any one scope is valid, preserving an unchecked wildcard. Dynamic client registration is enabled by default, but token authorization requires user interaction; a successful flow permits document, user, and team-setting reads, writes, deletes, and administration.

CVSS severity8.2
High
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper privilege management in Outline 0.84.0 through 1.6.1 allows remote attackers to gain unrestricted API access through OAuth. OAuthInterface.validateScope() uses Array.some() and returns the complete requested scope array when any one scope is valid, preserving an unchecked wildcard. Dynamic client registration is enabled by default, but token authorization requires user interaction; a successful flow permits document, user, and team-setting reads, writes, deletes, and administration.

The record

CVE
CVE-2026-43886
Published
May 11, 2026
Updated
May 11, 2026
Vendor
Outline
Product
Outline
Classifications
CWE-269, T1550.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 11, 2026CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 0.84.0, < 1.7.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Outline · Outlineversion=>= 0.84.0, < 1.7.0

Published CVSS scores

8.2GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-269Improper Privilege Management
T1550.001Application Access Token

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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